The present invention relates generally to a sensor and, more specifically, to a sensor with data storage medium.
Sensors for measurement of pressure, force, acceleration and temperature are frequently applied and employed in the measuring technique. These sensors often have their own identity or characteristics, i.e., the sensors of the same type and of the same construction have different sensitivities or other properties. As long as only a single type of sensor is used in a particular measuring set-up, the individual adjustment of the evaluation device to the individual sensor may be handled well and reliably.
It is more difficult to prevent confusion if a plurality of sensors of the same construction size are used or if, in the mounted state, just the connector plug thereof is accessible. This is, for example, the case with combustion engines, gas or steam turbines, die casting machines, die casting tools, extrusion machines, punching machines, crash walls, etc. or otherwise in the measurement of forces, pressures and/or accelerations. Thus, it is important not to confuse the sensor's own individual data. The data specifications, in whatever form, should be assigned definitely and unconfusably.
It is known to assign to a sensor, e.g., piezoelectric sensors, such as acceleration sensors, pressure sensors or force sensors, the data specifications of the sensor in an electronic storage medium. It is possible to store data, such as sensitivity, date of calibration, sensor type, serial number, person who carried out the calibration, etc. on this electronic storage medium, e.g., an EPROM. Moreover, it is also possible to directly store on the storage medium the adjustment parameters for the evaluation device, to which the measurement data of the sensor are transmitted for evaluation. By means of these data from the storage medium, the sensors adjusts the evaluation device directly by itself.
In order to achieve the required safety in the evaluation of the measurement data, it is also necessary, with these electronic storage media, to clearly and mutually assign measurement sensor and data storage medium. This may be achieved, for example, by integrating or incorporating the data storage medium into the enclosure of the sensor.
By using sensors, such as piezoelectric pressure sensors in an environment where high temperatures are encountered, sensors with data storage media incorporated into the sensor enclosure are no longer suitable. Electronic data memories, such as EPROMS, do not operate at temperatures over 150° C. to 200° C. and are destroyed.
Therefore, the data storage medium has to be mounted away from the actual sensor outside of the high temperature area and inseparably connected to the sensor, if possible.
In piezoelectric sensors, such as pressure sensors, the transmission of the measurement signals is in a high-resistance manner. Generally, the data of the data storage media are transmitted in a low-resistance manner. Thus, the transmission of the measurement data and the data of the storage medium advantageously have to be carried out via separate conductors. This leads to connection cables, which do not enable any miniaturization at a reasonable cost. Additional difficulties arise, if in addition, the data medium has to be arranged in an inseparable manner outside of the sensor enclosure.
In this respect, it is an object of the present invention to provide an improved sensor. The construction principle enables transmission of measurement signals and data signals from the data storage medium with a connection to the evaluation device enabling a considerable miniaturization.
According to the present invention, the sensor assembly positions the data storage medium in the connection of the sensor and the data storage medium to an evaluation device and spaced from the sensor. The largest diameter of the plug and the cable is at most equal to or smaller than a diameter of a sensor enclosure in a mounting area of the sensor. The connection includes one or more of coaxial and triaxial cables.
By the special connection of the measurement signals formed by the sensor and the data signals to the pins and ears in the plug of the sensor, it is possible to design the connection line and the plug of the sensor in a miniaturized construction. If it is impossible to integrate the data medium into the sensor, e.g., because the sensor is employed in a high temperature area, the data medium may be integrated into the plug area, without requiring to choose a plug with larger dimensions. On the other hand, this enables the use of the typical mounting tools for mounting, such as socket spanners, by guiding plug and cable of the sensor through the socket spanner in the course of the installation.
These and other aspects of the present invention will become apparent from the following detailed description of the invention, when considered in conjunction with accompanying drawings.